need help with 125 valve adjustment

[locko90]

Hey, I was in the process of adjusting the valve clearence and ran in to a problem.
When trying to find top dead center the marks on the cam sprocket and magneto don't stay on the marks when I put it to the *t* line the engine moves it back and it doesn't want to stay on the marks.
Should I duct tap it on the marks so it doesn't move or should I leave it a bit off the marks ?
Plz help i don't want to go ahead with duct taping it on the marks if that makes the adjustment wrong.

 

[locko90]

I have gone ahead and done the inlet at .003 and the exhaust at .004. I left the flywheel mark off the dead center line (as it wouldn't stay there) and the cam sprocket mark a little bit above the tdc line. Now turning the engine over its making a click or tap sound does this mean the adjustment is wrong.
Plz help I'm really stuck here

 

[locko90]

I have noticed that the bottom valve is making the taping noise when it starts to go in. There is alot of play In it as well can pull it out and push it in a bit. What would this mean ?
Stress

 

[locko90]

k well got tdc marks lined up properly, adjusted valves, put spark plug back in gave it a kick (there's 2 times more compression then before) it started up with a knock in the head. fml.

anyone know what this means should I be trying to adjust the valves differently? (I think the exhaust valve is bad) or is this okay and should I just ride it and let it wear in?

please any help would be muchly appreciated.

 

[gottagetacheaperhobby]

These engines are quite noisy in the head. If it all lined up correctly and you used the right measurements which it sounds like you did, then I wouldnt stress

 

[my67xr]

Did you follow any particular method for finding TDC?
It sound's like you have adjusted them on the Exhaust stroke, not the compression stroke?


[video=youtube;QJciyJRJh8Q]https://www.youtube.com/watch?v=QJciyJRJh8Q[/video]

 

[locko90]

thanks heaps for the feedback guys,
well to find tdc I had the mark on the timing chain sprocket on the mark towards the top on the head, and the fly wheels was on the *T* line.

it didn't want to stay there on the mark, so I jammed it with some paper just near right side of the casing next to the flywheel.
when I adjusted the valves they were dead on both marks.
I had alot of trouble with the bottom valve, I would turn the engine over after both valves were adjusted to just see if engine is turning over all good, after a few turns id try and get the .004 feeler gauge back in there and it wouldn't go in like the clearance had changed. then I would readjust it. (I got it all good before I kicked it over)

could there be the possibility that because the valve clearance has been wrong for so long the engine has worn in like this and now that I have made the clearance larger theres play in the valve that's making the knocking sound?

oh and I tried to get the feeler gauges in the gaps before I undone the nut, and they wouldn't go In so the valve clearance was smaller then the right clearance.

 

[my67xr]

Cam sprocket marking should be lined up with the marking at the front of the head, like this
I think that's what you meant by top of head.

The only time the flywheel will try to turn back a bit is on the exhaust stroke,
So the compression stroke would be 1 full turn on the flywheel more than where it was.

When you turned it over to check it you need to turn the flywheel around 2 time's to get it back to the compression stroke so you can re check it.

 

[locko90]

yeah that's what I meant haha and yep that's where I had the cam sprocket when I adjusted the valves, and the fly wheel was on the *T* line.
guess it should be all good? could the cam sprocket and flywheel marks be wrong?

 

[my67xr]

The marks will be in the right position's, just as long as it was on the compression stroke both time's it was checked.
Both times the clearance's should have been the same,

There will be a bit of a ticking noise when the engine is running, that's normal.
If there isn't any ticking then it's time to check the clearance's.
Make it a routine to check them every 5 hour's minimum.

Maybe just watch that video i posted before and recheck the clearance's,
with them set at .003" and .004" you should only just feel them move once set.
And yeah, turn the engine over a few times to check that the valve's aren't hitting the piston before you try starting it.

 

[locko90]

well done a check of the valves today they were all good :thumbup: so I went for a ride on it and I gota say I think its got a bit more power, well its definitely got more compression that's for sure ahaha.
thanks again guys for helping me out!

heres a vid of me doing a few drifts on it after adjusting the valves, seems to be going good :cheeky-smiley-031:
[video=youtube;AHH1CMe9vjQ]https://www.youtube.com/watch?v=AHH1CMe9vjQ[/video]

 

[motorman]

Nothing better than rebuilding a motor and getting it all working again!! Good sense of achievment.

Just don't forget this thread if you ever do it again like I did. haha.

Damn decomp got me big time.

Nice drifts too!!

 

[locko90]

yeah man u said it, its definitely an achievement for me, I was going to get a mechanic to do it haha, saved me some money there
thanks again my67xr